Attachment for rules



R. TRANE.

ATTACHMENT FOR RULES.-

\APPLICATION FILED FEB4 21, 1922.

Patented Aug. 22, 1922.

LAQYUSQ,

|| lll SI1/venirci atten/w14 RAYMOND TRANE, OF OMAHA, NEBRASKA., ASSIGNOR 0F ONE-THIRD T0 CORDELIA. BOON AND ONE-THIRD TO EUSTACE E. ASHLEY, BOTH OF OMAHA, NEBRASKA.

ATTACHMENT FOR RULES.

agences..

Specification of Letters Patent.

Patented Aug. 22, 1922.,

Application led February 21, 1922. Serial No. 538,149.

To all 'whom t may concern:

Be it known that l, RAYMOND TRANE, a citizen of the United States, residing at Omaha, in the county of Douglas and the State of Nebraska, have invented certain new and useful Improvements in Attachments for Rules, of which the following is a specification.

This device is especially adapted for use with parallel rulers, particularly those employed for marking or plotting courses obtained from the compass, the object of the attachment being to prevent any slipping of either ruler after the course has been obtained and while it is being plotted or described upon the chart. The device, may however be employed upon any rule, and I do not desire to be limited to work of any special class.

The invention consists of the novel features of construction hereinafter described, pointed out in the claims and shown in the drawing, in which Figure l is a plan view of parallel rules having my attachment applied thereto.

Figure 2 is a longitudinal section through a rule (broken away) my attachment being shown in section.

Figure 3 is a section on the line 3 3 of Fig. l, one of the securing devices or members being shown in depressed position.

Figure 4f is a detail view of a paper engaging member.

In the drawing l designates parallel rulers connected by the usual pivoted bar 2, each ruler being suitably beveled along its outer edge, as indicated in Figures l and 3, and each rule is provided on its under face with a longitudinal groove 3.

As the attachments provided for these rules are identical in structure, and as but one would be employed if used in connection with a single rule, it will be sufficient if one is described in detail. The attachment consists in a sleeve t having oppositely extending base lugs 5 which are attached to and countersunlr in the upper face of the rule. At its upper end the sleeve has an annular liange 6. A rod or bolt 7 having a thumb-head 8 at its upper end works through the sleeve and through an aligning bore in the rule, the head 8 when depressed engaging a seat formed in the flange 6 of the sleeve.

The lower end of the rod 7 carries a hori- Zontally disposed bar 9, which normally rests in the groove 3 formed in the under face of the rule, and at its ends the bar is provided with downwardly extending spurs or prongs adapted, when rthe rod is de pressed, to penetrate the paper on which the rule is laid, and as there are two of these points at a ,distance from each other and the bar fits nonrotatably in the groove all move,- ment of the rule relative to the paper is prevented. A coil spring 1l mounted within the sleeve returns the rod and bar to normal position when thumb pressure on the head S is removed.

From the drawing and the above descrip-A tion it is thought that the construction and advantages of the device will be apparent to all skilled in the use of drafting instruments.

What I claim is l. The combination with a rule having a grooved under face, of a bar fitting nonrotatably and normally resting in said groove and having downwardly extending prongs at its ends, and means for moving the bar downwardly to move said prongs out of said groove. Y

2. The combination with a rule having a grooved under face, of a 'bar fitting non-rotatably in said groove and having points adapted to engage the surface on which the rule is placed when the bar is moved downwardly in the groove, and a depressible thumb member working through the rule and secured to the bar intermediate its ends.

3. The combination with a rule having a grooved underface, of a sleeve mounted on the upper face of the rule, a spring therein1 a rod working through the sleeve and rule and against the tension of said spring, a thumb piece on the upper end of the rod, said thumb piece seating in the sleeve when depressed, and a bar carried by and at right angles to the rod, said bar having paper engaging points and normally fitting nonrotatably in the groove of the underface of the rule.

In testimony whereof I aflix my signature.

RAYMOND TRANE.

' l/Vitness:

JAS. Bunnies. 

